Hidden (Cache)
(2005)

George and his family are being sent disturbing drawings and videotapes of their house. One tape shows a street and then a door in an apartment block. George meets the person inside and realises that it is a man called Majid, who he remembers from his youth. George's family was due to adopt Majid, whose parents died in a political riot in the 60's, when he was 6 years old, but George was resentful and told lies that ended up with Majid being taking to an orphanage for the rest of his childhood. George meets Majid again in his appartment, but Majid slits his throat. Majid's son confronts George at his work and denies sending the tapes or drawings. 

Thanks Ali D!